Pneumatic handheld grinding apparatus

ABSTRACT

A pneumatic handheld grinding apparatus includes a housing, a motor set received in the housing. A locking member is mounted to the housing to hold the motor set in place and a grinding disk is connected to the motor set so that the grinding disk is rotated when the motor is operated due to a compressed air.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a grinding apparatus, and moreparticularly to a pneumatic handheld grinding apparatus that is easilyassembled.

2. Description of Related Art

A conventional pneumatic handheld grinding apparatus in accordance withthe prior art shown in FIGS. 4 and 5 comprises a housing (5) having acavity (52) defined in the housing (5) and a skirt (51) downwardextending from a periphery of the bottom of the housing (5). A switchset (54) is mounted to the housing for selectively allowing thecompressed air flowing into the housing (5). A threaded portion (521) isformed on an inner periphery of the cavity (52).

A pneumatic motor (53) is received in the cavity (52) and a lockingmember (6) in mounted to the inner periphery of the cavity to hold thepneumatic motor (53) in place. The locking member (6) includes athreaded outer periphery (61) so that the locking member (6) can bescrewed onto the threaded portion (521) of the housing (5). The lockingmember (6) includes a series of indentations (62) provided to engagewith a hand tool for fastening the locking member (6) to the housing(5). A dust-proof cover (55) is longitudinally attached to the skirt(51) and a grinding disk (56) is longitudinally attached to the motor(53) so that that the grinding disk (56) is rotated when the compressedair flows into the motor (53) and the dust-proof cover (55) provides adust-proof effect during grinding.

However, a hand tool is unique and necessary to mount the locking member(6) to the housing (5) because the locking member (6) is mounted in thecavity (52) and the hand tool needs to longitudinally correspond to theseries of indentations (62) in the locking member (6). As a result, themanufacturing cost is raised due to the inextricable processes forassembling the conventional grinding apparatus.

For solving the above problems, another pneumatic handheld grindingapparatus, as shown in FIG. 6, is marketed. In the embodiment, the skirt(8) is separated from the housing (7) and mounted to the bottom of thehousing (7) to hold the motor (72) in place in the housing (7) bymultiple blots (82). Consequently, multiple threaded holes (71) aredefined in the bottom of the housing (7), and multiple through holes(82) are defined in the skirt (8) and each aligning with a correspondingone of the threaded holes (71). For defining the threaded holes (71),the thickness of the housing (7) needs to be widened. However, thehousing of a general handheld grinding apparatus has no thickness fordefining the threaded hole so that the mold for forming the housingneeds to be altered and the strength of the structure near the threadedhole is weakened.

The present invention has arisen to mitigate and/or obviate thedisadvantages of the conventional pneumatic handheld grindingapparatuses.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide an improvedpneumatic handheld grinding apparatus that is easily assembled.

To achieve the objective, the grinding apparatus in accordance with thepresent invention comprises a housing including a cavity longitudinallydefined therein for receiving a motor set and a threaded portion formedon an inner periphery of the cavity near a bottom of the housing. Ajoint laterally extends from the housing and is connected to acompressed air source. A valve is mounted in the joint for selectivelyallowing the compressed air flowing into the housing to operate themotor set. A lever pivotally mounted to the joint for actuating thevalve. The motor set includes a motor received in the cavity and havinga shaft longitudinally extending from the motor. A connector iseccentrically securely mounted to a free end of the shaft and a grindingdisk is attached to the connector so that the grinding disk is rotatedwhen the compressed air flows into the housing and operates the motor. Alocking member is securely mounted to the housing to hold the motor setin place. The locking member includes a through hole centrally definedtherein to allow the connector and the shaft of the motor set extendingthrough the locking member when the locking member is mounted to thehousing. A first skirt upwardly extends from the locking member and hasa threaded outer periphery screwed onto the threaded portion of thehousing and a top portion securely abutting the motor to hold motor setin place after the locking member screwed onto the housing.

Further benefits and advantages of the present invention will becomeapparent after a careful reading of the detailed description withappropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pneumatic handheld grinding apparatusin accordance with the present invention;

FIG. 2 is an exploded perspective view of the grinding apparatus in FIG.1;

FIG. 3 is a cross-sectional view of the grinding apparatus in FIG. 1;

FIG. 4 is a cross-sectional view of a conventional pneumatic handheldgrinding apparatus in accordance with the prior art;

FIG. 5 is an exploded perspective view of the grinding apparatus in FIG.4; and

FIG. 6 is a cross-sectional view of another conventional pneumatichandheld grinding apparatus in accordance with the prior art.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings and initially to FIGS. 1-3, a pneumatichandheld grinding apparatus in accordance with the present inventioncomprises housing (1), a motor set (2) received in the housing (1), alocking member (3) mounted to the housing to hold the motor set (2) inplace and a grinding disk (23) connected to the motor set (2) so thatthe grinding disk (23) is rotated when the motor is operated due to acompressed air.

The housing (1) includes a cavity (11) longitudinally defined thereinfor receiving the motor set (2) and a threaded portion (111) formed onan inner periphery of the cavity (11) near a bottom of the housing (1).A joint (12) laterally extends from the housing (1) and is adapted to beconnected to a compressed air source. A valve (13) is mounted in thejoint (12) for selectively allowing the compressed air flowing into thehousing (1) and operating the motor set (2). A lever (14) is pivotallymounted to the joint (12) for actuating the valve (13).

The motor set (2) includes a motor (20) received in the cavity (11) inthe housing (1) and having a shaft (21) longitudinally extending fromthe motor (20). A connector (22) is eccentrically securely mounted to afree end of the shaft (21) and the grinding disk (23) is attached to theconnector (22) so that the grinding disk (23) is rotated when thecompressed air flows into the housing (11) and operates the motor (20).

The locking member (3) includes a through hole (35) centrally definedtherein to allow the connector (22) and the shaft (21) extending throughthe locking member (3) when the locking member (3) is mounted to thehousing (1). The locking member (3) includes a first skirt (32) upwardlyextending therefrom. The first skirt (32) includes a threaded outerperiphery (321) screwed onto the threaded portion (111) of the housing(1) and a top portion (31) securely abutting the motor (20) to holdmotor set (2) in place after the locking member (3) screwed onto thehousing (1). A second skirt (33) downward extends from the lockingmember (3). The second skirt (33) includes an annular rib (332)laterally outwardly extending from an outer periphery of the secondskirt (33) and a series of indentations (331) defined in the outerperiphery of the second skirt (33) for user to easily mount the lockingmember (3) to the housing (1). A dust-proof cover (34) is attached tothe second skirt (33) and engaged to the annular rib (332) to preventthe dust-proof cover (34) from detaching from the locking member (3).The grinding disk (23) is mounted to the connector (22) and thedust-proof cover (34) partially covers the grinding disk (23) to preventthe grinding dust from being present all over.

As described above, the locking member (3) and the dust-proof cover (34)are sequentially assembled. The locking member (3) is easily secured tothe housing (1) because the second skirt (33) has a diameter greaterthan that of the first skirt (32). The operator can directly hold thesecond skirt (33) to rotate the locking to make the threaded outerperiphery (321) be screwed onto the threaded portion (111) of thehousing (1) even without using any hand tool.

Although the invention has been explained in relation to its preferredembodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the invention as hereinafter claimed.

1. A pneumatic handheld grinding apparatus comprising: a housingincluding a cavity longitudinally defined therein for receiving a motorset and a threaded portion formed on an inner periphery of the cavitynear a bottom of the housing, a joint laterally extending from thehousing and adapted to be connected to a compressed air source, a valvemounted in the joint for selectively allowing the compressed air flowinginto the housing to operate the motor set, a lever pivotally mounted tothe joint for actuating the valve; the motor set including a motorreceived in the cavity and having a shaft longitudinally extending fromthe motor, a connector eccentrically securely mounted to a free end ofthe shaft and a grinding disk attached to the connector so that thegrinding disk is rotated when the compressed air flows into the housingand operates the motor; and a locking member securely mounted to thehousing to hold the motor set in place, the locking member including athrough hole centrally defined therein to allow the connector and theshaft of the motor set extending through the locking member when thelocking member is mounted to the housing, a first skirt upwardlyextending from the locking member and having a threaded outer peripheryscrewed onto the threaded portion of the housing and a top portionsecurely abutting the motor to hold motor set in place after the lockingmember screwed onto the housing.
 2. The pneumatic handheld grindingapparatus as claimed in claim 1, wherein the locking comprises a secondskirt downward extending therefrom, the second skirt including anannular rib laterally outwardly extending from an outer periphery of thesecond skirt, a dust-proof cover attached to the second skirt andengaged to the annular rib to prevent the dust-proof cover fromdetaching from the locking member.
 3. The pneumatic handheld grindingapparatus as claimed in claim 2, wherein the locking member comprises aseries of indentations defined in the outer periphery of the secondskirt for user to easily mount the locking member to the housing.